Sand riddle



Feb. 11, 1930. Q F, NAAB ET AL 1,746,958

I SAND RIDDLE Filed May 2, 1927 Patented Feb. 11, 1930 Unirse STAT-ss PATENT rence GEORGE F. NAAB .AND .ALFRED 2B. ALTZ, OF CLEVELAND, OHIO, ASSGNORS NORTH AMERICAN MANUFACTURNG COMPANY, F CLEVELAND, OHO,

IORATION OF OHIO TO THE A COR- SAND RIDDLE Application led May 2,

This invention relates to sand riddles for use in foundries for the purpose of sifting the moulding sand commonly employed.

fin object of the invention is to provide such riddle with power actuating` means therefor which shall be of a rugged and simple construction adapted to withstand the conditions of hard usage met in foundry practice. More particularly the invention embraces an improved electrical actuating means such as a solenoid and arrangement ot the same in connection with the riddle sieve; and an improved mechnical circuit interrupter and arrangement of the same tor con- -1 trolling simultaneously the operation of the actuating means of a number of riddles.

Still another object is to provide a means for controlling automatically the actuating means of the individual riddle dependent upon its movement into and out of operating position over the work.

Further objects and improvements, and the exact nature of the invention will be apparent from the following description and claims taken in consideration with the accompanying drawings, in which Fig. 1 is generally an elevation partly in section and partly diagrammatic showing the general construction of one ot the riddles and details of the actuating means thereof, and the interrupter with its driving motor, and diagram` matically another riddle actuating means in the interrupter circuit; Fig. 2 is a section along the line 2--2 of Fig. 1 showing further details of the solenoid employed; Fig. 3 is a detail of one of the laminations of the solenoid core; Fig. l is a section along the section 4 4 Fig. 1; Fig. 5 is a detail plan view as in the plane of the line 5-5, Fig. 1; and Fig. 6 is a horizontal section as in the plane of the switch arm 27, Fig. 1, showing details ot the switch operating arrangement.

The principal parts of the riddle are a standard or base 1 adapted to be secured on the floor, a telescoping arm 2 adjustable by the thumb screws 26 mounted upon the base and carrying a sieve receiving member 3 and a solenoid assembly generally designated by the numeral fl; and a mechanical interrupter generally designated by the numeral 5 mounted at any convenient location and in connection with one or a number of riddles, as will be described. The member 8, is movably mounted upon the extreme end of the arm 2 as by suspension from a number of links 6 and comprises simply a ring flanged as indicated in the drawings to support the circular edge of the usual riddle proper or sieve 7, the extremity 8 or" the arm 2 being likewise circular so as to aitord free access to a sieve carried by the member 8.

As a preferred form of actuating means we employ a solenoid type of motor. rlhe solenoid comprises a core 9 built up in the usual manner of tri-polar laminations 10, supported upon thearm 2 by a pair of strips 11. The lower extremities ot each ofthe strips 11 carry between them a roller 12 upon which rests igor sliding movement lateral of the member 8, a strip 18 of hard non-magnetic material. Secured upon the strip 13 between the extremities oi the core 9 is a laminated armature 14, the arrangement being such that the armature 14 is reciprocable between the poles a and c of the solenoid core. The member 13 is in connection with the member 3 as by the link 25. Surrounding the path of movement of the armature 1s are a pair of coils 15 and 15 adapted tor alternate energization to move the armature 14 within vthe limits of the core poles and thus impart a shaking movement to the member 8 and the sieve thereon.

For the control of the solenoid coils we provide the interrupter 5 which comprises a motor 16 connecting through a suitable reducing gearing within the housing 1.7, with a disc 18 or' hard non-conductive material such as bakelite for rotation of the same at a relatively low speed with respect to that of the motor. Spacedat 180 relative to the disc are two pairs ot opposed or aligned brushes 19 and 19; each pair et brushes being spring urged to contact with each other but normally separated by that portion of the disc 18 between them. A portion of the periphery of the disc 18 is cut away as at 20, the radial edges of the cut away portion being preferably beveled to an edge as indicated at 21. The motor 16, solenoid 15, 15 and the brushes 19 and 19 are wired as indicated in Fig. 1, the switches 22 and 23 being included in the circuit.

The operation of the riddle will be as ollows: Assuming a suitable electric current which may be either direct or alternating supplied to the points L1, L2, closing of the switch 22 places the solenoid coils in circuit subject to the brushes. Closing of the switch 23 starts the motor 16 to rotate the disc 18 at a suitable speed relative to the natural period of vibration of the loaded 'sieve 7, through the reducing gears. As the disc 18 revolves the cut away portion 2O allows each pair of brushes 19 and 19 to alternately efr'ect contact with each other, breaking of the contact being accomplished by insertion of the peripheral portion of the disc between the paired brushes with a motion suiiiciently rapid to wipe the contacting brush faces free oi' any damaging arc. Assuming the switch 22 closed, as the brushes 19 contact the coil 15 of the solenoid is energized polarizing the ends a and b of the core and consequently moving the armature 14 from a position in Fig. 1 to a position abutting the pole a. A thin insulator 24 is provided on the ends of the poles a and c of the solenoid and the armature 14 is bumped sharply against the same at the end of its stroke, imparting a corresponding suddenly interrupted movement to the sieve 7 through the member 25.

rlhe disc 18, continuing in movement next separates the brushes 19 cle-energizing the coil 15, and thereafter allows contact between the brushes 19 to energize the coil 15. Energization of the coil 15 polarizes the ends b and c of the solenoid core, returning the armature 14 to the position indicated in Fig. 1 ot the drawings, with a motion similar to that already described; after which the brushes 19 are again separated by the disc, and the action described repeated.

As indicated in Fig. 1 by the diagrammatic representation of the solenoid 4 of another riddle, the interruption may be arranged for operation of a number of riddles.

Preferably the switch 22 of each riddle may be arranged tor automatic operation by a swinging motion of the arm 2, so that the solenoid of any riddle will be in the interrupter circuit only when the riddle is in the desired operative position over the work.

Such a switch arrangement is shown in Fig. 1, the portion of the arm 2 fitting over the vertical member of the base 1 being circuinferentially slotted as at 2a, the base member within having an opening as by being vertically slotted as at 12L and the switch linger 2T projecting into theintersecting portion of the two slots; whereby the finger is vertically adjustable on the base without disturbing the switch.

that we claim is:

1. In a sand riddle, a base, an arm arranged to swing thereabout, a sieve on said arm,

means for imparting sifting movement to the sieve, a circuit arranged to control said sieve movement, and switch means in said circuit and associated with said base and with said arm to be actuated by said arm movement, whereby the base may be located beside the work to allow the sieve to be swung over and .from the work, and the sieve will automatically have sifting movement while over the work and will be idle when swung therefrom.

2. In a sand riddle, a base, an arm vertically adjustable thereon and arranged to swing thereabout in any adjusted position, a sieve on said arm, means for imparting sifting movement to the sieve, a circuit arranged to control said sieve movement, and switch means in said circuit and rassociated with said base and with said arm to be actuated by said arm swinging movement independent of the vertical adjustment of said arm, whereby the base may be located beside the work to allow the sieve to be swung over and from the work, the sieve vertically adjusted on the base for proper sifting elevation, and the sieve will automatically have sifting movement while over the work and will be idle when swung therefrom.

3. In a sand riddle, a base, an arm arranged to swing thereabout, said base and said arm having openings overlying each other, a sieve on said arm, means for imparting sifting 1 movement to the sieve, a circuit arranged to control said sieve movement, and switch means in said circuit and arranged on said arm and having an actuatinginger extending into said openings whereby said nger will be actuated as said arm is swung.

4L. In a sand riddle, a base, an arm vertically adjustable thereon and arranged to swing thereabout, said base having a longitudinal slo't and said arm having a transverse slot, said slots being arranged whereby a portion Iof each overlies a portion of the other, a sieve on said arm, means for imparting sifting movement to the sieve, a circuit arranged to control said sieve movement, andswitch means in said circuit and arranged on said arm and having an actuating finger extending into said slots whereby said inger will be actuated as said arm is swung.

In testimony whereof we hereby aliiX our signatures.

GEORGE F. NAAB. ALFRED B. VALTZ. 

